Method and apparatus for requesting SIB in wireless communication system

Abstract

Provided are a method for a terminal for requesting a system information block (SIB), and an apparatus for supporting the method in a wireless communication system. The method may comprise the steps of: receiving, from a radio access network (RAN), an SIB list comprising one or more SIBs supported by a cell; receiving, from the RAN, SIB broadcast information indicating whether the SIB supported by the cell is broadcast in a broadcast control channel (BCCH) section; detecting an omitted SIB on the basis of the SIB list and SIB broadcast information; and requesting the omitted SIB from the RAN.

What is claimed is: 
     
         1 . A methodfor requesting, by a user equipment (UE), a system information block (SIB) in a wireless communication system, the method comprising:
 receiving, by a user equipment (UE) from a base station, a first system information block (SIB) including (i) an SIB list comprising one or more SIBs including at least one SIB supported by a cell from a radio access network (RAN) and (ii) broadcast status information representing whether the at least one SIB is being broadcasted in a broadcast control channel (BCCH) modification period; 
 receiving, from the RAN, SIB broadcast information informing the UE whether an SIB supported by the cell is broadcast in a broadcast control channel (BCCH) period; 
 detectinga missing, by the UE, an SIB which is included in the SIB list and not broadcast in the BCCH modification period, based on the SIB list and the SIB broadcast status information; and 
 requesting the missing SIB from the RAN, 
 wherein the missing SIB is an SIB that is not broadcast in the BCCH period among the SIBs comprised in the SIB list 
 transmitting, by the UE to the base station, a request for the SIB. 
 
     
     
         2 . The method of  claim 1 , wherein the BCCH modification period is a current BCCH modification period or a next BCCH modification period. 
     
     
         3 . The method of  claim 1 , wherein the BCCH period is one of a BCCH modification period or a BCCH repetition period. 
     
     
         4 . The method of  claim 1 , wherein the missing SIB is an SIB that the UE needs to receive from the RAN base station in order to perform a particular service. 
     
     
         5 . The method of  claim 4 , wherein the particular service comprisesincludes at least one of a multimedia broadcast/multicast service (MBMS) service, a device-to-device (D2D) service, a vehicle-to-everything (V2X) service, or wireless local area network (WLAN) interworking. 
     
     
         6 . The method of  claim 1 , wherein the missing SIB is requested from the RAN base station by informing the RAN base station of a service associated with related to the missing SIB. 
     
     
         7 . The method of  claim 1 , wherein the SIB list and the SIB broadcast information are received by the UE via particular system information. 
     
     
         8 . The method of claim  7   1 , wherein the particular system informationfirst SIB is a system information block that is always broadcastbroadcasted by the RANbase station. 
     
     
         9 . The method of  claim 1 , further comprising:
 receiving a probability factor from the RAN base station, wherein, based on a random number drawn by the UE that is less than or equal to the probability factor, the missing SIB is requested from the RAN base station.   
     
     
         10 . The method of  claim 1 , further comprising:
 receiving, from the RAN base station, a value tag informing the UE of system information to be requested from the RAN base station, wherein, based on the missing SIB that is the system information informed by the value tag, the missing SIB is requested from the RAN base station.   
     
     
         11 . The method of  claim 1 , further comprising:
 receiving, from the RAN base station, a number of a type of SIB to be requested from the RAN base station, wherein, based on the missing SIB that matches the number of the type of SIB to be requested, the missing SIB is requested from the RAN base station.   
     
     
         12 . The method of  claim 1 , further comprising:
 receiving, from the RAN base station, a set of SIBs to be requested from the RAN base station,   wherein based on the missing SIB in the set of SIBs to be requested, the missing SIB is requested from the RAN base station.   
     
     
         13 . The method of  claim 1 , further comprising:
 receiving the missing SIB from the RAN base station in response to the request.   
     
     
         14 . A user equipment (UE)for requesting a system information block (SIB) in a wireless communication system, the UE comprising:
 a memory; 
 a transceiver; and 
 a processor functionally in communication with the memory and the transceiver to connect the memory and the transceiver, 
 wherein the processor is configured to: 
 control the transceiver to receive, from a base station, a first system information block (SIB) including (i) an SIB list comprising one or more SIBs including at least one SIB supported by a cell from a radio access network (RAN) and (ii) broadcast status information representing whether the at least one SIB is being broadcasted in a broadcast control channel (BCCH) modification period; 
 control the transceiver to receive, from the RAN, SIB broadcast information informing the UE whether an SIB supported by the cell is broadcast in a broadcast control channel (BCCH) period; 
 detect a missing an SIB which is included in the SIB list and not broadcast in the BCCH modification period, based on the SIB list and the SIB broadcast status information; and 
 control the transceiver to request the missing SIB from the RAN, 
 wherein the missing SIB is an SIB that is not broadcast in the BCCH period among the SIBs comprised in the SIB list transmit, to the base station, a request for the SIB. 
 
     
     
       15. The UE of  claim 14 , wherein the BCCH modification period is a current BCCH modification period or a next BCCH modification period.  
     
     
       16. The UE of  claim 14 , wherein the first SIB is a system information block that is always broadcasted by the base station.  
     
     
       17. An apparatus configured to control a user equipment (UE), comprising:
 a memory: and   a processor to connect the memory, wherein the processor is configured to:   receive, from a base station, a first system information block (SIB) including (i) an SIB list including at least one SIB supported by a cell and (ii) broadcast status information representing whether the at least one SIB is being broadcasted in a broadcast control channel (BCCH) modification period;   detect an SIB which is included in the STB list and not broadcast in the BCCH modification period, based on the SIB list and the broadcast status information; and   transmit, to the base station, a request for the SIB.    
     
     
       18. The apparatus of  claim 17 , wherein the BCCH modification period is a current BCCH modification period or a next BCCH modification period.  
     
     
       19. The apparatus of  claim 17 , wherein the first SIB is a system information block that is always broadcasted by the base station.